1. Field of Invention
The present invention relates to a heat sink and a lamp using the same.
2. Description of Related Art
There is a significant amount of energy consumption associated with conventional illumination techniques. As a result, the development of techniques to realize lighting energy savings is one of the most important areas of new energy technology research. High-power and high-brightness light-emitting diodes, which are semiconductor light sources, are increasingly being used. Light-emitting diodes have many advantages including high luminous efficiency, low energy use, long lifetime, being environmentally friendly (since no mercury is used), rapid start, good directionality, etc., and as a result, have the potential to fully replace conventional lighting sources.
In order to bring the foregoing advantages into play, the junction temperature of light-emitting diodes must be decreased as much as possible with the assistance of highly efficient heat-dissipating mechanisms. Failure to sufficiently decrease the junction temperature will result in the brightness and lifetime of light-emitting diode lamps to be greatly reduced. Moreover, not only is the energy-saving effect of the light-emitting diode lamps reduced, but also, the reliability of the light-emitting diode lamps is directly impacted when the junction temperature is not sufficiently reduced. In some instances, serious luminous decay performance occurs or the light-emitting diode lamps may even fail.
A passive heat-dissipating approach generally used in a conventional lamp involves installing a heat sink in the lamp. The surface of the heat sink is exposed to the ambient air, and heat is dissipated into the air by natural convection. Therefore, in order to meet the heat-dissipating requirements associated with a high-power and high-brightness light-emitting diode lamp and thereby enable the same to operate normally without luminous decay performance, a heat sink with a large heat-dissipating area must be used. In order to improve the heat-dissipating capability of a lamp, an active heat-dissipating approach may be employed. That is, a fan module can be installed in the lamp, and exhaust flow paths are correspondingly designed in the heat sink.
However, a conventional heat sink with exhaust flow paths always has a poor layout, sometimes resulting in incompatibility between the exhaust flow path layout and the positions or quantity of light emitters. As a consequence, low heat dissipation is achieved, and the brightness and light uniformity of the lamp are negatively affected. Therefore, many in the field are endeavoring to design exhaust flow paths in a heat sink in such a manner to effectively improve the brightness and light uniformity of the lamp.